TEM investigation of grain boundaries in YBa2Cu3O7 thin films grown on SrTiO3 bicrystal substrates

Seo, Jin Won; Kabius, B.; Dähne, U.; Scholen, A.; Urban, K.

doi:10.1016/0921-4534(95)00057-7

Cited by 37 publications

(14 citation statements)

References 22 publications

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“…We have fitted our data to expression ͑2͒ considering t Ϸ 3 nm in order to deduce from the experimental t ratios. 17 In the fit m ratio is in the range of 10 22 so the carrier density is about 10 21 cm −3 which is consistent with the values reported in the literature for YBCO GBJJs. 18 A detailed analysis of the fits and the value of n for each geometry will be published later.…”

Section: Resultssupporting

confidence: 79%

Frequency analysis of the dielectric constant ofYBa2Cu3O7Josephson junctions fabricated on bicrystalline substrates

et al. 2006

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We have studied the electromagnetic parameters of YBa 2 Cu 3 O 7 Josephson junctions fabricated on bicrystalline substrates with different angles tilted around the ͓100͔ and ͓001͔ axis. Changing a technological parameter such as the junction width permits change to the resonant frequency of the barrier cavity. This change in the resonance frequency allows one to determine a frequency dependent dispersion relation of the dielectric constant ͑͒. We have explored the proximity to a resonance in the dielectric response and analyzed its resonance frequency and damping constant. In terms of a RLC circuital equivalence additional information on the inductive response is presented as a comparative study of junctions fabricated on substrates with different bicrystalline misorientations.

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Section: Resultssupporting

confidence: 79%

Frequency analysis of the dielectric constant ofYBa2Cu3O7Josephson junctions fabricated on bicrystalline substrates

et al. 2006

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“…This is very similar to GB's in the cuprate superconductors, where the boundaries were also found to be clean without any secondary phases and with the lattice distortions to be confined within 1-2 lattice spacings. [37][38][39] However, the grain boundaries in doped manganite epitaxial films are almost as straight as the GB in the underlying SrTiO 3 bicrystal substrate. This is in clear contrast to GB's in 5. ͑a͒ Sketch of the junction model for grain boundary junctions in the doped manganites.…”

Section: B Model Considerationsmentioning

confidence: 99%

“…the cuprate superconductors that are strongly faceted. 38,39 It is very likely that this difference is related to the different growth modes of the cuprate and manganite thin films. Whereas the cuprates show a pronounced island growth with the islands growing across the substrate grain boundary resulting in strong faceting, the manganites show a molecular layer-by-layer growth mode.…”

Section: B Model Considerationsmentioning

confidence: 99%

Low-frequency1/fnoise in doped manganite grain-boundary junctions

et al. 2002

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We have performed a systematic analysis of the low frequency 1/ f -noise in single grain boundary junctions in the colossal magnetoresistance material La 2/3 Ca 1/3 MnO 3−δ . The grain boundary junctions were formed in epitaxial La 2/3 Ca 1/3 MnO 3−δ films deposited on SrTiO 3 bicrystal substrates and show a large tunneling magnetoresistance of up to 300% at 4.2 K as well as ideal, rectangular shaped resistance versus applied magnetic field curves. Below the Curie temperature T C the measured 1/ f noise is dominated by the grain boundary. The dependence of the noise on bias current, temperature and applied magnetic field gives clear evidence that the large amount of low frequency noise is caused by localized sites with fluctuating magnetic moments in a heavily disordered grain boundary region. At 4.2 K additional temporally unstable Lorentzian components show up in the noise spectra that are most likely caused by fluctuating clusters of interacting magnetic moments. Noise due to fluctuating domains in the junction electrodes is found to play no significant role.

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“…Assuming for the relative dielectric constant r the value estimated for oxygen deficient YBCO, r Ϸ5, 34 and tϷ3 nm in accordance with microscopy studies, 35 we deduce that, when w is in the order of 10 m, the characteristic frequency of our circuit model f RLC ϭ1/(LC)…”

Section: A Electromagnetic and Transport Propertiesmentioning

confidence: 87%

Electromagnetic properties andHe+irradiation effects onYBa2
Mulas
¹
,
Quesada
²
,
Navacerrada
³

2000
Phys. Rev. B
18
0
14
0
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We have analyzed the electromagnetic properties of small and long YBa 2 Cu 3 O 7Ϫx grain-boundary Josephson junctions. The Swihart velocity increases with junction width ͑w͒ while the ratio of the relative dielectric constant to the barrier thickness (/t) decreases. We found that the product wϫ/t is approximately constant. These results have been explained in the framework of the filamentary model, where the barrier can be regarded as a disordered dielectric medium with a high density of superconducting filaments. Experiments demonstrate that a controllable variation of these parameters can be achieved by helium irradiation at 80 keV. We give examples of an enhancement of weak-link properties of junctions for doses in the range of 10 13 cm Ϫ2. Raising the dose we can sweep the modification of the weak-link properties from an increase of the junction critical current of about 10% to a severe degradation of the coupling energy of the barrier, although the superconducting properties of the electrodes always worsen gradually.

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TEM investigation of grain boundaries in YBa2Cu3O7 thin films grown on SrTiO3 bicrystal substrates

Cited by 37 publications

References 22 publications

Frequency analysis of the dielectric constant ofYBa2Cu3O7Josephson junctions fabricated on bicrystalline substrates

Frequency analysis of the dielectric constant ofYBa2Cu3O7Josephson junctions fabricated on bicrystalline substrates

Low-frequency1/fnoise in doped manganite grain-boundary junctions

Electromagnetic properties andHe+irradiation effects onYBa2
Mulas
¹
,
Quesada
²
,
Navacerrada
³

2000
Phys. Rev. B
18
0
14
0
View full text Add to dashboard Cite

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TEM investigation of grain boundaries in YBa2Cu3O7 thin films grown on SrTiO3 bicrystal substrates

Cited by 37 publications

References 22 publications

Frequency analysis of the dielectric constant ofYBa2Cu3O7Josephson junctions fabricated on bicrystalline substrates

Frequency analysis of the dielectric constant ofYBa2Cu3O7Josephson junctions fabricated on bicrystalline substrates

Low-frequency1/fnoise in doped manganite grain-boundary junctions

Electromagnetic properties andHe+irradiation effects onYBa2Mulas1, Quesada2, Navacerrada3 2000Phys. Rev. B180140View full textAdd to dashboardCite

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Electromagnetic properties andHe+irradiation effects onYBa2
Mulas
¹
,
Quesada
²
,
Navacerrada
³

2000
Phys. Rev. B
18
0
14
0
View full text Add to dashboard Cite